The instant invention relates to apparatus for conveying sheets of paper, and more particularly to such apparatus which is capable of conveying collations of paper of varying thickness.
Conveying apparatus for transporting sheets is used in a variety of machinery, one such example being an inserting machine which inserts paper documents into an envelope. The sheet handling apparatus upstream of the inserter typically has conveyors which advance the sheets one at a time or in sets along a feed path which will ultimately deliver those sheets to an inserting station in the inserter. The sheets may be accumulated and stapled and then sent forward to the inserting station. Sometimes the accumulated sheets are stapled and then folded before being inserted into an envelope.
Many of the sheet conveyors employ continuously moving, O-ring style belt members, and problems are incurred when the sheets initially engage the O-ring belts. In this style conveyor, the lower reach of an upper belt lies very close to the upper reach of a lower belt in order to exert pressure on the documents to be conveyed. However, when large sets of sheets (i.e. up to 50 sheets of 20 lb. paper) are fed through the conveyor, a large amount of pressure builds between the belts being deflected by the sets that the sets jam. The conveyor must feed these sets of sheets, whether 0.008 inches thick or up to 0.225 inches thick, at equal rates, with no jamming occurring, in order to insure that the inserter throughput is maintained.
The instant invention thus provides a continuously running, O-ring belt type sheet conveyor which is capable of feeding a single sheet or a set (collation) of sheets at equal rates without any jamming occurring.